Circadian Arrhythmia: Shiftwork, Travel and Health

Abstract

There are many reasons why employees' working hours may come into conflict with the inherent (circadian) rhythms of their bodies. Vital services such as police, ambulance, hospitals, electricity must be maintained 24 hours a day; expensive equipment is more profitable if used continuously; machinery such as furnaces may be damaged if shut down.

Work patterns which conflict with our circadian rhythms may produce fatigue, a tendency to make errors, accident-proneness, ‘jet-lag’ and perhaps ill health.

Those most at risk are shiftworkers and aircrew: whilst the latter must cope with changing shift patterns and time-zone changes, the former are required to adapt to changes in work/sleep patterns against an environmental background disruptive to such an adaptation.

More difficulties arise when we consider those with chronic health problems since employees on long-term medication may not be able to reconcile an unvarying drug regimen to an ever-changing work pattern. Furthermore, there is evidence that the potency of drugs may vary according to the time of administration.

There is much to be learned about the health effects of shiftwork; here we review what is known.